Cape Gannet

Morus capensis - The Cape Gannet

Cape Gannets are easily recognised for their eye-catching black and white plumage which appears silky, giving them a graceful, swan-like appearance. They have distinguishing black lines around the beak and on the face (which almost look as if they have been applied by a skilled make-up artist). The long, pale blue bill is pointed with serrations close to the tip and the feet are large and webbed between each toe.

Did you know? From a height of 30 metres, Cape Gannets dive 10 metres under water on a mission to catch their piece of the seafood buffet.

When seen in flight the snow-white body with the black tail, primaries and secondaries, and bill are most striking. The golden crown and nape which gradually become white on the neck are characteristic of this beautiful bird. Impressively graceful in flight, Cape Gannets have a clumsy gait on land.

Size

Range mass: 2 - 2.6 kg.
Range length: 84 - 95 cm.
Range wingspan: 170 - 185 cm.

Habitat

Within its normal range, Cape Gannets are restricted to the continental shelf, at no more than 100 km from the coast. Occasionally they have been recorded on oceanic waters.

Distribution

Cape Gannets are restricted to the coast of Africa. They are found in waters off the Western Sahara, around Cape Agulhas and the Cape West Coast to the Gulf of Zanzibar (Tanzania) and occasionally to Mombasa (Kenya) on the east coast of Africa.

They can also be found at the Bird Island Nature Reserve and Verlorenvlei, both connected to Lambert's Bay, the St Croix Island Marine Reserve (just off the coast of Port Elizabeth), the West Coast National Park and the Grotto Bay Coastal Nature Reserve (both less than an hour from Cape Town).

Breeding is restricted to just six small islands, making the Cape gannet vulnerable. This is due to the over-exploitation of its prey by human fisheries, pollution, and human disturbance. In South Africa, the colonies can be found in Lambert's Bay and Bird Island (under the administration of CapeNature Conservation) and Malgas Island (under the administration of South African National Parks).

Diet

Cape Gannets feed on shoaling pelagic fish such as sardines and pilchards, eating up to 300g daily.

Socialisation

Cape Gannets are social birds. Gannets pairs may remain together over several seasons. They perform elaborate greeting rituals at the nest, stretching their bills and necks skywards and gently tapping bills together (see photograpgs above). Cape Gannets are not strictly migratory and the majority of birds remain within 500km of their breeding site, all year round.

Reproduction

The breeding season begins in August when the pairs form and nests are rebuilt. Nest mounds are built on guano and are unlined. A single blue egg is laid and quickly becomes coated in brown guano. Most eggs are laid in October. The eggs are incubated for approximately 40 days. Both adults incubate the eggs using the webs of their feet. Both parents care for the chick for 97 days before it goes to sea.

Incubation

40 days.

Life Expectancy

Estimated at 10 to 20 years.

Predators

Great white pelicans and humans.

References

Birdlife International; Animal Diversity Web.